Supervisory control system



De.18,192s. T.U. WHITE ETAL 1695908 sUPERvIsoRY CONTROL SYSTEM Thomas I) white and John E. Gardner ATTORNEY ec. 18, l 928.

1,695,908 T. U. WHITE ET AL sUPERvIsonY CONTROL SYSTEM f Filed April 21, 1924 9 Sheets-Shet "3'.

Q N 01W fi E vr' im f 07 im l A T m E l *i f g q Wm 7 T# 58- N ln a f'f'\ Q E' v3 l DN s N M y n; 1 Nl T INVENTOR Thomas .d Whfq and f 1 wlTNEss Es:

John .C Gardner; R BY f A'TTRNEYL De@Y 18,1928.

T. U'. WHITE ET AL SUPERVISCRY CONTROL SYSTEM Filed April 21, 1924 9 Shees-Sheet 4 Thomas U. Whie and John Ear'dner- ATTORNEY D@ 18,' 192s. 1,695,90g. f

T. U. WHITE ET AL.

SUPERVSORY CONTROL SYSTEM Fired April 21, 1924 9 Sheets-Sheet 5 Subs/Jhon WITNESSES: Thomas u, whine and# I John E Gardner ATTORNEY Y mvENToRs Dec: 18, 1928.

WITN'ESSES:

,"r. U. WHITE -ET Al.

SUPEHVI SORY CONTROL SYSTEM Filed April 21, 11924 'i 9 Sheets-Sheet INVENTORS Thomas U W/Pr'fe and fo/m IST Gard/7er t ATTORNEY Dec. 18, 1928. 1,695,908 T. IU. WHITE ET Al..

SUPERVISORY CONTROL SYSTEM Filed April 21, 1924 9 Sheets-Sheet 7l 1,695,908 T. U. WHITE ET AL sOPERvIsORY CONTROL SYSTEM Filed April 2], 1924 9 Sheets-Sheet 8 INVENTORB Thomas l Whire and lom E Gardner' 4M BY ATTORNEY Dec. 18, 1923,V

IT 'U- WHITE ET AL 1'695908 sursnvlsonv CONTROL ss'rms Filed April 21, 1924 9 sheets-sheet e mvENToRS l'Thomas 2. W/w're and rnn E Gard/7er ATTORNEY as that in which it occurs.;

Another object o'f our lnvention'is to ar' Patented Dec. 18, 1928.

'UNITED STAT-ES PATE-'Nr OFFICE.'

THOMAS -U.- WHITE, `or HTTsBUBGn, AND conn E. caminan, or WILKINSBUBG, PENNSYLVANIA, assumons; Tov wnsTrNeHoUsn ELECTRIC a MANUFncTUnING COMPANY A CORPORATIONflOF PENNSYLVANIA.

surnnvison'r coNTnoL SYSTEM.

. Application nieanpru'ai, 1924. serial No, denses.

Oui` invention relates to supervisory con- .trol systems and-particularly to. systemsA tor supervising and controlling, from acentral'A point, remotely-disposed electrical apparatus.

One ofthe objects of our invention `is to provide means for supervising, at a central point or 'dispatchers oiice, remotely-dis- `posed electrical apparatus arranged so that the operation of the remote apparatus is signailed at the oilice in the identical sequence l range'c ircuitsfor signalling the-operation of apparatus units at a distant-point -or substa tioninthe sequence that these operations take place, even though the operations occur before vthe selective apparatus has had time to function.

A Still. further object of our invention is to providemeans for signalling at the central point, all yoperations of the apparatus units under supervision, whether such action takes place as a result. of'contrelfrom the central.

point or dispatchers oice or takes place automatically under the control 'of currentresponsive devices-at the station.

In practicing our invention, we provide a group of supervisory lamps and' controllingkeys for each substation to be used for supervising and controlling the apparatus units therein. There is a trunk line connecting the dispatchers otlice to each substation. Associated with oneend of each trunk -line is adirectively controlled Aautomatic switch. Also,

in each substation, there is an automatic sending equipment associated with the trunk line. In addition, in the dispatchersolice, an automatic impulse-sending device is provided for controlling the operationfof' the 'directivel controlledswitch at the substation and whic is operated'in response to the operation of the control keys.

Referring now -to' the drawings, comprising Aliig'ures 1 to. 9, inclusive, there is shown,-

by means of conventional diagrams, suicient of the Acircuits and apparat-us to enable our invention to be readily explained and understood.

Figures 1 to 8, "inclusive, .when placed side by sidewith the corresponding lines at the ends thereof in alinement, illustrate the cir,-

.cuits 'of our complete system.

Figs. 1, 7 and 8 are diagrammatic views of the equipment located in the load dispatchers office, While Figs. 2 to 6, inclusive, are similar views of the selective and control equipment in an automatic substationI of the system. v

Fig. 9 illustrates ay modification of our invention.

vWhen one ot the apparatusunits atlthe station or substation changes its condition, under `automatic control, the automatic impulse sender in the substation operates to send a series of impulses over the trunk line As a result of this operation, the automatic impulse-sending device in the dispatchers .ofiice is caused to operate.; Series of impulses are thus sent over the trunk line to operatethe directively controlled switch in the substation. The operation of the switch causes the selection and operation of the desired apparatus unit. The operation of the unit, of

course, causes the supervisory signalling devices to be changed in the same manner as* if thev unitl were operated under automatic control.

Means are so provided that, if two or more apparatus units operate at substantially the same time, theautomatic sending device at the'substa'tion will function to send the supervisory signals reporting such opera'- tions tothe otlice in identically the same sequence as that in which the units operate.

Referring now more particularly to Fig.' l,

a key K. This key is' one et several groups 0f keys and isof the ordinary double-throw type that is automatically returning to normal after being actuated in either direction. A 'switch F is a finder switch'of the usual rotary type, as illustrated in the patent to Clement No. 1,107,153, the wipers. et which in the .upper left-'hand corner thereof is shown ics ms in fpfwardairecuon only. The finder Switch isproyvided. with four wipers-112310" `126, inclusive, each ofwhich is adapted" tol gshwninrigs. .Relayssoofo soamclqswe; "constituting'the relay group RG-#2, control theoperation of-supervlsory lamps L..

-5 live contact members. The wipers of/they finder switch F have no normal posi'tiom;`

are two of a plurality of Vline switches under .To the control of a master switch MS of the.

1f The switch CD' is acode-sending'switcli,.'jtype illust-rated'fin .fitkens' Autematici'V n similar'in mechanical construction tothe finder switch ,mOn/ account of differences 1n circuit desi'frn, the -.^s'w1tch CD performs diffrent functions/than the switch F and is rotated to' .normal/positional'. the end of each operation. '/I Fiv 2,4 there is shown a connector 15 A"switch This switch is ofthe same general mechanical construction as the switch F. However, i ts`circuits have been so designed "as to enable it to be directivel operated. V'Fir'. 3 shows two roups G-l and RG-A of-sellecting relays, t e relay group IRG-I being the primary selecting group and the clays 400 to 404', inclusive; Fig. Liare .25 those selected'by theo eration ofthe-selective relays'of Fig. 3. elys 4 05 to'407, in elusive', control the operation' of ajcircuit breaker C. The'cicuit breaker 4G may be ngstne of anumberf'of interrupters-at the.'`

ation. AsA shown,l thef circuit breaker/m C, irl/conjunction with otherapparat/us/(nbt' 5 shown), 1s adaptedto initiatehoppa-ation of a rotary converter RC// l 4;/

.A; switch PS is somewhat simila'iii me-A 85 chanicallconst-ructionfto thefinde'r "switch F and controls the .operation of relaysgsucli /.-as4l3 and ,41.4. .'lfherelays ilandy 414 are two of a number of similar'relays and are 0f the multi-contacttype.A Relays l15 and.

- 4u 416' are associatedwith the circuitbreaker'C "'andfcontrol the functioning of the codesend= in equipment, as will appear later. f clays- 503 and 504:,V Fig.- 5, are 4associated with relays 413 andl414 and control the op-1 eration of mlays 508 and 509 in the rela-yl group RG--Scomprising relays505 to 509,

inclusive. R'elaysiQ to '502, inclusive, uref m switches 'are similar to'the's'witcheslFrand Cn'cviously'described.' 'In ig."7'is showna. connector'H--/siniilar to the. connectoruH vdescribed above.' 4Relay goups1RG--4 and HGr- 5, shown-"in los Fig. 8, A are selective -relays-sixixilar tothose the substatiomf lThisl equipment has notbe'rw [`elephony vols-i2', page "2'06.; #The' line` switches', such -'a's LS,'fare ,of theoi'dmary i `Keithcui plunger` type, and the plungers of all the line switcles nre'maintaincdbcforc. au idlel trunkvv by the' operation of. the master4 switch MS. The line switches, such as LS, arel of the well-known, self-.alinin type. That is, after being operated when t vey are 30' released, they areumnediately placediunder the control of the masterswith. The niaster switch MS is of the usual typear'n'l is'adaptcclr" ,I

shown in the dr wings;v asit i'siidtaiiartof the lpresent invention and: is' wel1 known.v` n" operating,itlie 'circuit brakervfcnncts c" .rotary converter RC to'fthe` alternating-fcuifju;

there are other functioiistobe performed, but these willbe-handle'd by therautom'atilcj n#Y trolling devices. The closureof: the. ciicu breaker Q -islall y thiit.. vv g -.i.'are concerned'vit in the resent invcn'tion. L W- it 1 tleiwfiperseftthc fglfefttconforment@entre;aufm". l

duct'ori 413, relay 502and arnature 521and -inclusive, byfreason' of the. deenergization :ot

' relay, such as 504,associated with the bank contact precedingbank 'contact 547 in amanner that will appear more fullyhereinafter. e

' iWhen'the circuit breaker G ceses, afcircuit is'com leted extending from ground by way contant .nfld armature'. 419, Pellet contact of spring-456andfsaid spring, con-- itsvbarkfcntact tobatteryf The relay 416 is energized'and .operates to prepare certain.

circuits fwhi'ch will be described later. l'The relay'502 is energized overthe above circuitand operates to repare a clrcuit for the relay 62,8 l of-the 'coefsending s witah CD-l at armature 529, to place ground upon the haul;

Contact 547-.at armature' 531,1'to establish alockingV circuit for itselfat armature 52S i' from ground throughfbattery, back Vcontact and ,armature 521, 'winding-fof relay 502, front contact and armature 528, conductor 481, front contact andarmature.otrelay 416, through [the relay 416, pallet switch 429. and arrnature.,419 to ground and -to 'momentarily complete a: ci1euit' extendino from. ground by wa of 'armature-'527cm its front contact, con uctor 476, v bank contact with Awhich wiper 440 is vin engagement, normally-closed spring controlled by arma- ,tiire 431 andfrelay 410 .to battery..

'lherelay 410, upon zoperating, opens its' original 'energizing circuit at .armature 431,

.' completes v a .flocking circuit lfor itself at this sarne arniature, completes a circuit for the switching-.relay 411 .andithe motor magnet 412 in series at armature 432, and atr armature 433 connects the test Wiperto the above ciry cuit at a point-midway between the switch# ing reay and the motor magnet. The motor magnet of the preselecting switch PS now o crates to advancetheiwipers 440 to 442 inc usive, into engagement with the next setof bank contactsV vincluding --the banll contact 445, thcbank contaqt444 havingfbeen previously grounded lby V,the operation of the m1851504. .Y 1 v Whenengagement' is made with this. set of i bank contacts, the 'short-circuit is removed from the relay 411 and this relay is enerized in series with thernotor magnet 412. h e relay 411, upon-operating, opens one 'point 1n the test circuitat armature 436; and

. at armature 435 opens the lockingcirciit of .i the relay 410. The relfiy 410 is dccnergized' to prepare a circuit for itself and to open 'the circuit ofthe -switching` -reav 4111 which i-r deenergized. The wipers' 440 to 442, in-

' c] 11i-ive, of the prcselecting switch'now restin engagement with the bank contact set which includes the ban-k contacts 445 and 447.

By reason of the grounded wiper 442 being in engagement with the bank contacti447",A the relay 413 is energized'and this relay operates to connect relays-,such as 415 and 416, with. i

relays, such'as 501 and 502. Another resultlv of the movement ofl the'switch wipers is that the circuit of the 'relay 414 is opened. Tho'- `relay414 Ais deenergized to open the original energizing circuit of the relay 504. 'T ho reiay- 504 does net decnergize at' this time. in YViewl of the fact that its locking circuit has .been previouslycompleted. Y

Another result of the operation oi the relay' 413 is-that a circuit is completed extending' from ground byway ot' working contactfof spring 451 and said'spring, conductor 477, rcsistor'-l and relay 50f3 to battery. 'lhe re. lay 503 is operated -ioren'iove ground from the bank contact 5 5() at-va'rxzzature 532i, to cstablish a locking' circuit for itself at thofront contact of this armature and to place ground upon the bank contact 445 al armature 532.

jonergization of the relay 503. vThe relay 506'v '.lhe operation of the rela) 503 also causes the.'

operates to disconnect ground from the bank Contact 549, thus preparing a circuit thatis ef'- fectiveupon the `subsequent operation oi' the consecution control switch CCS.

lVhen round is placed uponthe bankfcontact 547 y the operation ot' the .relay 502', a locking circuit i prepared for the relay 51'() and the relay 511 is' energized. The relay 511 operates to complete a circuit for the relay 510 in seriesvitl`i the magnet 512 and to connect the testwiper 51T to a point inidway between the switching relay and theniotor magnet.. There is no ground potential present upon the bank contact 546 and, lconsequently, tlie'relay 510 is energized.v The relay 510 operates to open the circuit of the' relay 511, to establish a locking circuit for itself at armature 554 and to open one point in the testing circufit at armature 553. 'lh'e relay 511 is deenergized to open the original energizing circuit of the relay 510. Another result'of the operation of the relay 510 is .that a circuit is completed extending .from ground hy way of front contact andl armature 552, conductor 562, back conleo tact and armature 610, inagnet`603, and back ing fronrground by way of wiper (i1-4, bank- Contact 6.18, conductor 563, armature- 529 and its rontcontact, conductor 564 and relay 628 to battery. The, relay 628 is immediately operated over this circuit. v v

,As a result ofthe energization of the relay 628, the. circuit of the stepping magnet 60?:

. 5 lay, and 'back contact "is opened at armature 640 and, at armature ,641, ai circuit is completed which from ground' by way of, said argiaturejaii its front contact, winding-oflW-acting rc-V. and arinat'uie652 l to .battery.- -Another result ,o tlie/energiza- 'extends ,sufsult o this operation, a'cir'ciuti over the conductors'690 :and69`1j for/thalme relay/ 798v oiftleconnectoH--'I latjthej"dis l pmliers o ii c e,v Fig." 7. Upon operati'nga armature 731, tige-i relay 708 completes/a c cuit for the slowl Y associated bank'contact,armature609 and its .tactand winding Another circuit in parallel with that described-- above, except -tliatdt goes by way .of armature (i44 and its back Contact and armature 15 643and its frontcontact, may be traced Yfor energizing relay G25.l The relay 627, upon operating, atits-.armature 639vcloses a cir; cuit. for the relay 626.` i

At this point, it may be well to mention the pcculiareonstruction of the armature 639 of the relay 627.v The armature 639 is weightedand is. so constructed that, when the relayl 627 is 'kleenergized,'the'armature-"-Tle energi'zatiou 'ofthe' relay T 6391vibrates for some tune on account'ot momentum. The* adj ustmcnt 'between the front.andback contacts-is so marie that 'the' armature-639, 1n decreasing the afr'nplitudef -of its operation, tirst permanently opens the;

circuit V`of-tlie relay 625., 'llheoperationf the relay Y625lis Withouparticular function atlhe'present;time v1e relay 626, upon operating,iat its armature 638 closes a .circuit.{o1- therelay-630 and at its 'armature 637 establishes {a}2 circuit which extends from .4 ground. byway of armature 641 and its front contact, winding of repeating relay 600, ar-f' mature ljand its front contact, and'to bat?- tery by -wayo f ba'clr contactand .armature 65 on the steppi ng magnet 634 of the code-` se dingswiteh C Df-l. c L The relay- 630 s energiaedefroma pre.. 'viously mentioned ,circuit and, upon voper-v atinglit-1closes` a circuit ati-armature- .646,1 A which extendsrfrombatteryfby way of front contact and Said'armature, winding of slow-- releasiiiig re1a`y, 632anci baek contact' and' ar- "m'ature 6,06 to ground; The relay632 upon operating,.at a. 1mature 650 closes a circuit for thefslwf'relea'sing relay 6.31. .By the rn/ 1 its 'iront Contact to,lnaftteryifvr attracting its armatures,t1e1re1ay-1706Tcloss a circuit for/th/eslow-,releasing relay `7051311. 75

point in` the. release c' rcuit/ff"removesy ground mature 7 25 closesiujcujcuit forthel relay?880,1i i

ing, at itsarnatre' 721 prepares aholdingf circuit; for/itself,l renifves battery yfrom lthe conductpf756' at armature 722,;.at armature l 720 opens' one point in the circuit of the 'relay' 85- 7 03 Vand at 'armature 719 closes a circu-itjor tti/ slow-releasing relay v701;' l

I'ne'rely j' 'p rcpalres'certain circuits which function later. The/magnet 709, upon'being.energizedyplaces .90 itsV 'pawl in position to operate'the*switch' l openthecircuit oftlierela 70S-ei' fcon-1 f f nector H-l. The deenergization o'f thelline 195 shaft uponthe dcenergizationioftlie mahnct The rela 880, upon energizing','establtishe s net 709.. The retraction of'the armature: of

thefmagnet 709 causes itsassociatedi'pawl'te'5,1

advance. thefswitcli sliat-ca1Ty1ng`tlic switch? 110 v upon the c0nductorf'75t6-at/the arri; opens theoriginal/enerbm'zing p he relay SSO {uf/1 `rm`ature 30and,1.atarnm 1y-.1- 728, closes a circuitfoibthI 'relays/70,15:

closes alockingeiruitvfqr'it gth'e'sarmature 8 71-,jandatarrnatuiie' loses a circuit pened'thecircuit of the slow-.releasing-relay" 2633. -fter'a short interval, this relay isdcenergize'd and-'opens'the circuit of the vstep-L ping magnet634" at armature 651. The mag- `net'63finis immediately deenergized to advance the wipers 655 to 658, inclusive, intoengagement with the first set of bank contacts and,

at armature 652,-closes the circuit ofthe repeatmg relay 600 and'also-the circuit of the' close the: circuit ofthe'stepping magnet'634 l and the repeating relay 600 is energized to close the clrcuitofthe'line relay '708 to the a connector H -L The alternate operation of and ope`rates,` at armaturec605, to open the circuit of thestep'ping mavuet' 634` and toV fro.

prepareanother 'circuit at time' front contact 'of this armature for the said magnet. An additional result'of the operation of the relay 601 is thatthefcircuit'offthe slow-releasing relay 632 isopen'edat armature'-606. V After a short intervaloftime, th'erelay 632 is decuergized to open the circuit-ofthe slow-releasf ing relay 631; 'Upony theretraction of the f 'iii'maturej649 of the relay 631, a circuit is completed .extendinggfromground by wa mature`601andlits front contact, t 1e back of arcontact and the'armature 64:9, front contact andarmature Vlg'vin'nding of stepping magnet 634, wiper 657 and its associated vbank con-j tact, and`'armature 646 and its front contact to battery.

f- The'fmagnetlf634: is energized over this circuit an'cljactuate's its armatures to position its peating relay i600.'V By the movement of the` switch Wipers,"occurring responsive to the deenergization of the magnet 634, the circuit of associatedpawl, jto' open the circuit of the slow-releasing relay 633, and also to open the circuitfofthe repeating relay 600.- The slowreleasing'relay-633`is deenergized, after an intervalotime, to open'the circuito thev steppingmagnet 634, which' i'sdeenergize'd ,.to again close thercircuit of the slow-releasing relay 6,33 'and to close the circuitot the rethe relay'GOl is opened and thisrelay is dee'nergized to open the circuit of the magnet- 634 yatarmature 605, vat the back contact of this armature-to lprepare` another circuit for, the mafrnet, and to close a circult at armature 606 for the relay 632.E The operation ofthe re- 4 lay 632 closes a circuitfor the relay 631.. The

operation ofthe relay 631 closes the original steppingcircuitlof the magnet 634. ,The alternate operation of the relay 633 and thel magnet 634 again occurs until the wipers 655l A 4to 658, inclusive, are advanced into engagement with the bank contact set which inclu the bank contact 663. ,L d y During the operation of the code-sendin switch CD-1,while its wipers were rotate `insearch of the contact set which includes the hankcontact 661, thecircuit of the relay 600 was intermittentlyopened and, consequently, the circuit of the line'relay 708 of the connectorH-l.. It is true that the operation of the slow-releasing relay 633 indirectly con' trols the speed-of the operation of the repeat ing relay 600 vand the speed of operation o the'line relay'708 of the connector 'H-l.l It

is also true that, at each fleenergization of the relay 708, the circuit of the slow-releasing relay 706 is openech In order to obviate any ,false operation, which would occur were the relay 706 to be deenergizedbetween deenergizations of the relay 633 in the switch CD-1,

the time constant of the slow-releasing relay 633 is materially fasterthan the time constant of the slow-releasing relay 706.l

Each time the circuit of the line relay 708 is 'les'A opened, this relay is deenergized to openthe A circuit of the slow-releasing relay 706 andalso the circuit of lthe stepping magnet' 709. The magnet709 is thus deenergized a plural# ity of times to advance the wipers 735 to 738, inclusive, into engagement with the bank contact'set, which corresponds to'the number of impulses sent over the trunk line, as deter Y vmined by the number of. steps that the codesending switch CDT-1 has taken to find the bank contact set including the contact 661. It will be assumed vthat the bank contactset selected by the connector H-1 includes the contact 760.

As the wipers of the connector H-1 have been rotated past the normal set of bank contacts, the original energizing circuitof the slow-releasingrelay 705 is o-pened.- However,

the relay 705 is not deenergized until the termination ot the first series of impulses.y Thls result is by reason of the fact that', at each retraction ofthe armature 731 of the line re lay 708, a circuit is closed for the relay 705.

By the deenergization of the relay 705 at the end of thc first series of impulses, the circuit of the slow-releasing relay 7 01 is opened at armature719, at armature 720 acircuit is prepared for the relay, 703, and a circuit is'v closed at armature 722\which extends from battery by way ofvba'c'k' contact and armature 722, conductor 757, winding of relay 808, con-- ductor 747, bank contact 760, wiper 735, front contact and armature 710, and front'con'tactand armature 726 to ground.` Therelay 808 is energized over this circuit' and operates to group.BG-' 5 at-thearmature 8275, to close its locking circuit' at the front 4contact olf'ths ,armature toground on the conductor' lith-Which has been groundedl previously. by,V y.operaopen the locking circuits of the relays in-the of the relay 707. Y Another result of thel lreleiis-i'ng rela vgI'63-in'll 32 'Y energization of the relay 808 that, at the ar".-tng-switch G -.-1 'are deen'ergized'Duringmature 826, a selecting'circuit 1s prepared... the adyancernent of the switch Wipers to their 658, inclusive, are-brought intov cngaemcnt i is` completedhv -v wit-h the bank contact set which includes the contact 663, as previously described, a circuit uch extcndsfrom ground byV ductni' 561, bank contact 544, wiper '515, wiper second psitionFt-he operation, of the arniature rlcauses the eergization of the relay 703; The operationof this 'relayis Without function at the present timer- `Whenf the" wiper 736 engaoes the nintliyfele'vcnth ,and

thirteenth sete? bank]contacts;l a circuit is waypf- `front contact and armature v552, concompleted. for the 1 'elc'.}," 7 04. The rela-yi 704 ductor 562,-w1per612, bank contact 616, conupon*beingenergized, closes afcircuit for theslow-releasing relay 701a'tthe v'armature 715` bank contact l545, front contact and ar- 4at the armature 7117 prepares'acircuit for nitui'e 530, conductor 66, bank c ontact663,

. circuit of the stepping magnet 634"atthe anP- rtljie relay 703 is ivitvhout'ffuncton atthis lm wipiler 656 and relay 6 01 to battery.

e retay 6I isenergizeclver theabove maintaining itselfcnergized, at armature 716 L opens the, ircuit of the"relay (703, and at arrnatureF 18 disconnects the battery ,from

circuit and operates, as beore,`te"npen ithe the cn'ductor 756;` `The deenergization of mature 605 and to open the circuit .of the sloxy: releasing relay 632 at armature 606. -The slow-releasing relay 632 is deenergiged to open the circuit of the slow-releasing relay 631, which also-retractsitsarmature. As a= resultof thelattcr 0 eration, the stepping magnet 634 is operate -to open the circuit ot' the interrupter relay 633, which retractsits 'armature to open the circuit ot' the stepping leasing relay 701 -`at armature715, preparing l i l `ergired to advance the switch wipers 4655 to 'mit relay'j703ii'd,it rnatiire 718, completes"4 658-, inclusive, into engagement with the next @and this rclay retracts its armatures.

The'dnergization of the'relay 601 opens the circuit of stcppingmagnet 634 and c oses 'circuit for the slow-releasing relay 632.

1 The rela 632 isenergzed to establish af cir- Abeing energize cuit for erela 631. The latter relay, upon reestablishes the circuit of the stepping magnet. 634. The stepping. magnet 634 now intermittently operates 1 to ,ativan-.1el the 'wipers 655 to' 658, inclusive, until they are brought into-engagemeijt'jvith` 738, inclusive, into engagement'wi'th the bank the twenty-fifth set of bank contacts.'

Durin the second advancement ofthe. Wipers o the code-sending switchg-eacht-il'nev the stepping magnet 634 operates, the circuit of the repeating relay 600 is openedfa-ndthis relay retracts its armature to produ'ceia corresponding number of interruptions in `theA circuit of the line relay 708 of the dbnnector `H-l. .Upon each retraction of the armature 731- of the relay 708, the. circuit onthe stepping magnet 709 is opened and the mag' net operates to advance the wipers 735 to contact set 'which corresponds to the number A i of impulses sent over the trunkline, as lde-` termined' bythe second movement4 of the wipers. of the code-sending switch CD-'-L It will be assumed that this contact set include'sthe bank contact 761.

When the wipers of the connector are broug ;ht' into this position, n o more impulses are sent over the trunk lineuntil the slow-` time.

7 35to 7 38; inclusive, oft'hemonnector H-l have been 'rota-ted int engagement with the bank contact;v set including the contact l761,

the -circuit ofthe slow-releasing relay 704 is opened;A f The 'relay704 retiacts its armatures, .thereby openingl the. circuits of the slow-re a' circuit at armature 7l6iontheslowfrelcas-- a. circult whichx eittends-rorn "battery 'by wav 'of'said armaturefandits back contact,

\conductor 756, winding offrelay', con-' swatch CDJ-11s steppedaround to its tweneasement ,with their twenty-fifth to-their twentyffthfsetfof bank contacts opens the circuitk of-:thelrela 627 and also the energizing circuitn of the levireleasing relay 625. :The relay 627'irmnediately re- `tracts its armature.' y,reasori; of thefpeculiar constructionbf the; armature 6 30,`prev1 osly described.- tliisfrniature vibrates for an intervahn time, thiiszalternatelyclosix'iie the circutsfoi the .slowreleasing relays. 5.

and 625.- --For the 'reason expla' ed previous- 125 ly'fthe relay 625 isthe first t!) retract :Bal-mr wiesprepares scircuit Another result ofthe s'wtchsgfipersof the codescning-witchffbrought ,The deenergization ofthe relay 625' orthe relayog,

l lh sending switch' (3D- F1V andare brought to linto engagement with'thetwenty-,fifth set of bank contactsis that'a `circuit 1s completed A extending fromgrou'nclby way' of wiper 655,

'bank "coiitct 660, "and Winding of relay 629 to battery.v The relay 629. operates to open another pointinfthe'energizing circuit of the relayl'625 atarinat-ure 644g and to close tbe circuit of the relay 602 at the .armature G45.

Upon' being energized, the relay 602 operatesto establish another circiiit'forrtlic relay 'G28 atarinaturc 608 and toclose a circuit at armature"G07 which "extends to ground by ivay Ofsaid armature and its front contact,.

wiper- 611, bank contact' 615, conductor 5G() aud'ivi'nding of relay 5,00 tovbattery. The re-v .layv 5001s 'energized overthe above vcircuit and operatestov establish a locking circuit for itself in 'series'with the relay 416 at armature 520,'"a`d atariature 521 to -open the circuit ofltliei'elay:509L`and also the original energizing' circuit of the relay 416.- The relay1502fis-deenergized toA open the circuit of tli'e 'relay 5,10 at'arinatlire 531 and to restore certain'jotliercircuits 'to normal.

The relay' 510 is deeneigilzed to remove ground ffromtlieconductor 56:?- at armature 552, to prepare a circuit for the relay 511 at arinat'ure'? 555;-andto'complete a'circ-iiit extendingfroiirbattery by way of back contact andar'mature 56 6,"wiperA 519, bank contact 545,`-and9i\viitling' of relay 504,'to battery. This{cit-cuit?serves* to shuntSthe relay 504, whicli'is-deenergized.'1 Tlie removal ofA ground from the conductor 562 opens the starting eireuit'ofthe 'finder Switch F -1. `The relay 5071 is hdeenergizedf'tof remove ground from the coiid1i'ctor2'4'5 andf to replace ground upon the lbank'contactl The replacement of ground u on 'the bank-'contact 547 causes the eiiergizatior'rof the' relay 511. A circuit is now' completed extendingr`v from ground by way ofwviper 518. arinatu're 555 and its back contact, andfwindii'ig of relay 511 to battery.

i Ther relay 511'; upon operating. completes a circuitifor. theiswitching relay 510 and for Vthemtorl`magnet'512 in seriesxat armature 558, `'and atrniature 557 connects tliejwiper 517to `tlieabovecircuit at; a point between thegsivitchingjrelay"and-the inotor magnet.

As there is jgrou'iid present. on `all th'e bank contacts associatedwith theiwiper 517, ex-

i cept the baikcontact 549, the switching re- -lay 510 willLbeslibrt-circuited by reasoirpf the'relay 503 4being operated, and the motor i'iiagnet'512 will operate to advance the switch i Wipers 515 to 519, inclusive, one step into engagementgwith' thel bank contact set coinprisins: the ibankcontacts 544 to 548. inclusive. WhenthejsWit-li'ivipersare brought into engagementfwith this' set of bank contacts,

.. there being no groundl potential present upon tliebaiik contact 546,-the sbortcircuit will be'remQVed'mm the windt@ otlie relay, A 510 and the "switching relay will operate in series with'jthe motor magnet, the latter re- Vthe 'Bv the operation ofthelconsecutioii conj trolsu'itcli CCS, circuits are prepared Where- 4by, when the next circuit breaker operates,

mainling ino erative by reason of the high armature 555,-

a code identifying this operation will be.

transmitted immediately to the dispatchers,

oiiice.I The manner in which this sequence I is maintained, when -a plurality of interrupters operate in. quick succession before the codc-sendin;v apparatus has ha d time to function.l is by the conjointoperation of the pref selecting switch. PS. the trunk selecting refV lays, such as 113 and 411. ltbc lockiiiga'elays, such as 503 and 504. and the consecutioii vcontrol switeh CCS. 'lliese operations will be described iiioie fully hereinafter.

Referring now to the operation of th equipment at the dispatclicrs utilice,` iii the connector H-l, thea-clay 7 0'3 ywhich has beenv energized by the operation of the armature .731 on the line relay 708 is deeiiergized, by'

reason' of the cessation of the operation of the a-rinature"d1. The operation of this re# relay4 702 is also deenergized. These vresults'.

are caused by the fact that the repeating ref lay 600 is retained energized for an interval after the `.vipers o'f the coil`e-sending switch CD-- -1 engage the twenty-fifth set ofbank contacts. Upon i'ctracting its armatures, the relay 702 closes ay circuit, which extends from ground by way of back contact and airmature 713, conductor 755, winding of low resistance relay 882,'arniaturc 89.6` and its 4front contact. front contact and armature 820v and Winding of relay S00 to'battery.

4This circuit 'serves to energize the itllay 800. Y

The energi'zation of the relay 800 closes a cir-` euit for the supervisory lamp 81B and'opens.

the circuit of the supervisory lamp 817'.' By

reason of these changes in the. supervisory .signalling devices, the dispatcher is n ppraised of the'change in position of the cir-v cuit breaker C kat the substation.v The operation of the relayuSSQ lopens the locking .cir -..V cuit for the'neliiyxSBO at armatliiefB'I; T ha `relay 880'imiiijdiately i'etracts itarmatui'eii The relays 880and 882 are provided for the '12? 1 purpose bf checking the operation ofthe as 'will' ap,.

@supervisory signalling devices,

pear more fully hereinafter.

:Returningr now to the operation' of the code-sending switch CDT-Lathe slow-releasloo lay is without function lor the present. They ling relayf'i626 isnally deenergizedpfand it opens thecircuit of the relay 600 at armature 637l and, at armature 638, it opens thecircuitfofthe relay 630. The deenerization of twenty-fifth position and remain there for an interval/1 Bv th'is circuit arrangement, false operati/on of the supervisory-signals is prevoided, because, should either the switch itb'erelay 630,'fopens the circuit'of the slqngmCD-F-l ixrtlxesulistation 1er, the connector p releasing'relay 632 at armature 646 andfnt" armaturesj/Gi'gand 648, completes a circuit theldispatchers iide get-out of synclfiromsinwith? the other, the wipers' of .each of thesmtches -willnot. bein their twenty- '0 .As a result of the Wipers ofthecod-se'ndf mature and back` Contact, winding Fu of/steppingma et-634, armature 647 and iter-the supervisoy signals will -not beoper'ated.

hijack Contact?, tlii-AtWenty-lifthbank contact 'with'. ivllch thef'wiper'j658 is in engagement, said wiper, an'dj'jl'iackfcontactv and armature yf 652i()battery -lfh stepping magnet- 634 is 15 energized overtliis circuitand operates to restore-thewipers'g655 'to 658, inclusive, to their norpial 'positionsf-whereupon the circuit of the magnet 634 Aeration ceases.v ff

isi-opened and its op;

'fth position simultaneously; Consequently,

. When'there isnfo 'change in the supervisory signals, the.`relay`882 is not energized. Cnsequent-l ,"therelay 880reinains energized. Now', wenl'the'lrelay 706 i's 'deenergized, a s

.,before'desc'gbed, circuit vis completed exljetending from" groundf by 'Way of armature A l728, and'it'sfliacklcontact, conductor 740', ar-

mature 883;' and Lital fronticontact, conductor 'if-184,:jand iyind'inghof relay 1,91 to battery.

The relayl 19.1', u n'being energized, causes ing switchvbeingv-broughtfo their nornalfpo-e, the finder switc F 'and the code-sending 'sition, the circuit of the relay SQQ-SQJQDBQ switch CD lto function to'send out a checking an/.dthis relay retracts its armatures t`op`en. code 'the circuit of-the relay 602. The slow-releas--l subsequently.

re1ay.632,`upon' retracting its'arinaturc,' ,In the'samemanner; as above' described,

` .opens thecicuit--of--theslow-releasing relay. anyV change in 'positionrof my of the con- 631, which is also deenergized. The relaytaetors,or otherapparatus units, causes the '602, upon retracting its armatures, opens the., linder switch F-l, the code-sending 'switch circuit ofthe-relay 628 at armature.608`,'and CD-l and the connector H--l to e operatarmature'GO'opens the original'energizng atedto controlthe actuation of t-hesuperrircuit of the relay 500. .The relayl 500 is not 'visory signals. Themanner in which ysuperdeenergized at this time by reason of the fact visory signals are sent to the dispatcher when that it, is maintained 'energized in series with Va. plurality of breakers operate in qu'ick'sucthe relay 416 until 'the :irc'uitv breaker C :cession will be described later.

i changes its`con'dition. The deenergization It'will now be assumed that the" circuit of the relay 628 in the code-sending switch ,breaker C at thev substation is'closed' and' CD-l merely restores certain circuits to thatthe loaddispatcher desires to open it. v their normal condition.- The deenergization In order to accomplish thisresult, the disof the relay 600, which occurred-immediately patcherY operates the double-throw key K in /after the-deenergization of the slow-releasing a direction to momentarily close the springs relay 626, opens the circuit ofthe line relay shown on the right.

- 708 of me connector H-1. The operation of the key Kcloses a circuit As the circuitof the relay '708 is opened, which extends from t-he positive pole of the this relay is deenergized to'open the circuit battery B by wa of. the workingcontact of of the slow-releasing relay 706.v Upon respring' 100, nsai tractingits armatures, the relay 706 closes', 106, conductor 183, front contact and, arma-- a circuit for the stepping magnet 7 09 which'l ture 814 and to ground. The vrelay 106 is the results otjir'hizh will-be described' spring, winding o .relayl 'etends from battery by Way of wiper 7 37 in -r cngagementwith the twenty-fifth bank contact, said bank contact, the back contact and -nrmature 732, back contact and armature '727, and winding. of stepping magnet 709 to ground. The stepping magnet 709-operatcs y to restore the wipers 735 15o- 738, inclusive, to their normal posit-ion..

In the abone described manuel', the appa- A'1.\ratu's is-released` following the sending of the supervisory signal to the'dispatcher, notifying him of the automatic operation occur.

Itwill be .noted that th`e -\supeivi sory4 signal 818 -isrn'otactuatedaimnediately after' the'. o series -of impulses which caused its selec n, 1,1.: Itis operated when the wipersf nnector H`1 are brought Into their'- energized overthis circuit and o eratesto establisha locking circuit-for itsel at armature 173, over al path extending from the positive pole of` battery B, armature 17 3 and llts front contact, s ring 177 and its resting contact, winding o relay 106, conductor 183,

and front contac 'and' armature 814 to ground. The oper tien olthe arn'iature'l')J of the relay 106 closes a circuit for the monitoring lamp 174. lamp remains lighted through the sending operation, even after ion lio

the key? K restores 'to noriiialfin order to in- A form the dispatcher that the desired 'code is being sent. Another result of the energizetion oftheirelay 106 is that, at armaturev 104.-, a circuit is completed .which' extends from ground by way of armature 104 and-its working contact, winding of stepping magnet 109 of finderswitch-F, armature 132 and its back contact, and-back contact and armature- 120 to battery. As the stepping magnet 109 in#y terrupts its own circuit, it operates as a buzzer to advance the switch wipers 123 to 126, inclusive, until they 4are brought into engagement with thebank contacts 127 to 130, in-

elusive, which is the contact set associatedv with the key Kin the finder F.

When the switch'wipers are broughtinto engagement withthis setof'bank contacts, a circuit is closed:which'feirtends from ground' through the'windingbf'relay 108 b y way of the' common conductor'134,v which is common to all the keys in the group,'front contact and armature 101, bank eontact.='1 30, wiper 126 and relay '113 to battery.- The relay 113 isenerg-zedfover this circuit'and, upon operating, opens'the circuitoi-the'stepping magnet 109, thus. stopping the-'operation of the-finder switch, landclosesa circuit for the relay 111- extending frombatteryby. :way of armature v120 and itsjfront contact,"winding-,ofrelayfj 111, bank -contaetpw'ith' which A'wiper "160 engagement and saidwiperlto ground, vand at armature 121 closes a circuit which' entends:` from ground by way of a'rinature'121 and its'-l front contact, winding ofslow-releas'ing'l relay 143, andarmature 152 and its back con? tact to battery. The relay 111, uponbeing energized, closesa circuit for the slowreleasing relay 110 at itsarmaturc 117. -The armature 117 of the relay 111 is conbrates for an interval of time afterwards, the

structed in amanner similar to the armature 4of the relay 627 of the code-sending switch C13-land, consequently, when the relay 111 becomes deenergized, the armature 117 Virelay 110, upon operating, at armature 115 closes a circuit for the relay 140 and, at ar-A mature 116, establishes a. circuit which extends fi'or'n ground by way of armature 121 and its` f ront contact, winding of repeating relay 144, front contact and armature 1'16 and armature 152 and its back contact to battery.

. lherepeating relay 114, upon operating, at

its'armature 154 closes a bridge across-the 4conductors 180and181 extendingto the substation, whereby the line relay 200 of the connector H is energized.'v

The line'l'elay 200, upon operating closes --al circuit for the slow, releasing relay202 in.. parallel with the stepping magnet 207. The A stopping magnet 207 is encrgizedto place its associated pawl in position to actuate thev vswitch shaft.' -The slow-releasing relay 202,

.upon being energizcd,*closes a cireuitfor the' slow-releaslng relay 203. AThe latterl relay pcratessto energize the slow-releasing relay 206. The operations of the'se relays have the salue functions as described in connection -wxth thc'conncctorH-l.

Returning now to the operation ofv the code- .sending switch CD, the relay 140, upon operating, at its armature 148 closes a circuit for the slow-releasing relay 141.` The relayv 141, upon attracting its armature, establishes a circuit for the slow-releasing rela.y 142..

The latter relay, upon being energized, closes i a. circuit'whichextends from -groundby way of armature 155 and its back, contact, f'front contact and armature 151, -front contact/ and A armature 153, winding of magnet 146, wiper 162 and its associated bank contact, andgarmature 148 and its front contact to battery.

The stepping magnet 146 isenergized over this circuit and operates to place its associated and 143 at the armature 152. The d eenergization of the relay 144 opens the Circuit of the line relay 200 of the connector H at the substation.

deencrgized, opens the circuitof the .stepping jmagnet 146, which is also deenergized, t0 vre- "establish the circuit of the relays 143 and 144, 1and to advance theswitch wipers 160 to .163,

4pawl in position to actuate the switclifshaft. v and also to open the circuit-of the relays 144V The slow-releasing relay 143, upon being.;y

-is completed that extends from ground by Way.A

of armature 103 of relay 106 and its front I contact, wiper- 125, banl{ 'contact 129, bank 'f contact 165, wiper 161 and winding of relay I l l100 145 to battery. The relay 145 is energized over this circuit and, upon operating, opens the circuit of the stepping magnet 146 at armature 155, at the front contact of'this armature prepares another circuitv for the magnet and at armature `156 opens t-he circuit of the slow-releasing* relay A141.

The rotation of the switch, of course', ceases.

The slow-releasing relay 141,v upon..being -I deenergized. opens the circuit of the slowreleasing relay 142.- -After a short interval, the slow-releasing relay 142 retracts its armature and closes -a circuit which extends from ground by way of armature and its front contact, back contact and armature'll, front stepping magnet-146,'wiper 162, bank Contact with which said wiper is in engagement, and frontcontact and armature 148 to battery.

The stepping magnet 146'operates to attractits armature, thereby placing the pawl in ac- .tuating position-and'opening the' circuit of cuit ofthe relay 144.. In accordanccwith'the vfirst operation of the codc-sending-switch CD, a series of inthe slow-rcleasingrelay 143 and also the cir-' terruptionsis' produced in the circuit of the .1 15 contact and armature 153, winding of the line relay 200 of the connector This relay is deenergized aplurality of timesfin response thereto. As a result of the -retractions lof sequentl ation of the armature 209, is deenergized. As

thearmature 209, the circuits of'the slowreleasing relay 202 and the ma net 207 are switch, the rel?,1 201 isenergized to ground theoonducto'r 60. It will be assum'ed that the bank Contact set to which the wipers 225 to 228, inclusive, are stepped includes the bank 'contact 2,30.-

'During the interval that the slowlrelcasin T: i s141and142 in the code-sending s'witc areybeing deenergized,V the slow-releasin re- --lay v 203 of` the connector H, Awhich has een maintained energized by the continued opera result of this-operation, a circuitis completedrwhich extends from ground by way of armature 211 'and its front contact, armature 221iand its front contact, Wiper 225,` bank Contact 230, conductor 262, winding of relay"A 306' conductor 271, and armature 215 and its back contact to batt'ery. The relayA 306 is 'energized over thiscircuit .and operates-to close a locking circuit for itself at armature 322 to ground on the conductor 2,60.

Returning now to the operation of the codesending switch CD, the deener'gization ofthe 'slow-releasing relay -142 closes a' lcircuit for the' magnet 146 Awhich is energized to place its associated pawl in 'actuating ositionand to open the circuit of the slow-re easing relay Wh 143 and also :the circuit of the repeating relay ,144,4 :The slow-releasing relay 143, u on being de energize'd, opens the circuit of t 1e stepping magnet 146, which is deenergized. The retraction of the armatures of the magnet 146 advances the switch wipers another step and also closes the circuit of the interrupting relay 143 and the repeating relay 144.l -By the movementof the 'switch wipers,the circuit of the relay 1'45 is opened and this relay retracts vits armatures to open the circuit of the magnet 146 and to close the circuit o f the slowreleasing relay 141. The energization of the relay 141 closes the circuit of.,th e relay 142.

T e operation of the relay 142 again starts the operation of the stepping magnet 1,46. The magnet 146 is now intermittently operated tofadvance .the wipers 160 to 163,inc1u sive, into engagement with the bank contact which includes the contact 166. .A cir-l cuit is now closed which extends from und by way of armature 103 of relayJOfand its front contact, armature 119 .of relay 108 and its front contact, wiper 124, bankcontact 128, bank contact 166, wiper 161 and 'winding of relay 145 to battery. The relay 145' is energized to momentarily stop the operation of connector H in Vthe same manner as'before l during the second movement of the wipers 5,

of the switch. Y The line relay 200 operates to control the operation of the stepping magnet 207 in advancing the wipers 225 to 228, inclusive, into engagement with the proper bank contact set, which, it willbe assumed, includes the bank contact 231. At thetermination of 'this series of impulses, the slow-releasing relay 204, which has been energized while the twelfth, thirteenth and vfourteenth set of bank -contacts and has been maintained energized switch -wipers were being rotated past the bythe operation of the line relay 200,*is de# i energized., A circuit is then closed which extends from ground by way of rontcontact Y and armature 211, armature 221 and its front contact, wiper 225, bank contact 231,--conductor 268, Winding of relay 303, conductor 270, armature21'9 and itsback contact to batcircuit and attracts its armatures to establish 3 50 and to preparen circuit at the armature 319 forthe relay 402 in the substation. 3'

Going back-now tothe operation of the code-sending switch CD, the slow-releasing relays 141 and 142 operate, as before, and the tery. The relay 303 is operated over this 'a locking. circuit for itself at the armature magnet 146 is intermittently operated after f an lnterval of time to advance the Wipers 160 to 163, inclusive,into engagement with the twenty-fifth set of bank contacts.

en the wipers 160. to 163, inclusive, are brought into engagement with the twentyiiftli set of bank contacts, the circuit of the stepping magnet 146 is opened and its 'operation ceases temporarily: 'A circuit is' also completed which extends from ground by Way of wiper 160 and its associated twentyfifth bank contact, and winding of relay 112 to battery. -The relay 112 is energized to prepare a circuit for the stepping magnet 109, the function of which will be described subsequently. Another result of the rotation Vof the wipers to the twenty-.fifth position is 110 isthus maintained' energizedfor an -interval afterlthe relay 111 is deenergizcd. In

. t e same manner as before described, thc

' wipers of the connector H are brought into engagement with their twenty-fifth set of bankcontacts.

Now, during-the'interval that the relay 110 in the dispatchers office is maintained energized, the slow-releasing relay 205 in the connector H at the substation is deenergized and a circuit'is completed which extends. from' battery byway ofthe back contact and v3.-', tion control switch CC 50 that the operatingco i O dispatchers oiii 1,695,9oe y armature conductor` 269, conductor 374,

windingof relay-'402, conductor 371, armature`319 and its front contact, and front contact and armature'323 -to ground.A The relay- 402 is operated over 'the 'above circuit to complete a 'circuit for the tripping coil 409 of the circuit br ler C. The circuit breaker C operates to .sconnect the rotary converter e pallet sfwiteh`429.

A relay 415, working contact of spring 452 and v 'said spring, conducto-r 472, relay 501 and back contactand armature 521 to battery. The relay 501 is operated to establish a locking circuit for itself at armature 523, to prepare circuits for the code-sending switch CD at armatures 524 and 525, to place ground upon'the bank contact 550 at armature 526 and to complete a circuit armature 522, for the 'line relay 410 of the Y preselecting switch PS. The preselecting switch new takes one step in the saine manner as befo'redescribed, and the relay 413 is deenergized and another relay similar to it is energized. By

contact 550, the line rela 511 of the co'nseclris energized, as is the switchlng relay 510.

The :code-sending operation new takes H place in the same manner as before described, except for a slight diferencein the equipv.40 lment at the dispatchers olice which occurs by reason of the relay 106 being locked energized when the'la-mp 81S is lighted. By

the deenergization of. therela'y 800,'whieh occurs bythe sending back of the ,'e'ode, the retraction of the armature 814 of thezrelay 800 causes the relay 106' tofbe deenergized he deencrgi'zation'of the relay. 106'opens the operating circuit of theftinder `switch F 'and the codesendin switchCD, ,insuring gc Will not be sent to the substation again.v 1 v The locking relay 106'also Vprovidesmeans whereby, i for some reason or other the code is not transmitted properly either to the substation orto the dispatchers o lice, the

sending operation will reoccur in' both diree- `l tions until ,the corresponding contactor or apparatusl unit is operated and the correspondmg supervlsoryjsignals are operated `at the Returning-uma'A to the operationgof the I cod'efsending switch CD, it will be remenb sbered that the circuit of the slowreleasing the clreuitof the steppingv magnet 109 -is closed. If no other relay, such as 105 or 106,

relayv 110 is finally opened 4by the cessation RCland to o en the circuit of the relay 4.16v t this relay is deenergized to momentarily, a't' the grounding 'ot'. the bankA of the vibration of the armature 11'79"y The relay 110 upon being deenergized opens the circuit ofthe slow-'acting-relay 140 at the armature 115, atthe amature 411 opensv the .circuit of the relay 144, and at the armature 114 closes acircuit that extends from'bat- `tery by-way of front'contact and armature 1-18, armature 114 and itsbackcontact, back contact and armature132, winding of step-v ping magnet 1094 and the front contact and armature 104 to ground. The magnet 109 'is' circuit' to advance the operated `over this wipers 123 to 126, inclusive.

'The slows-releasing',-relay 140, upon -being..-

deenergized,v 'opens the circuit of the slow-re! leasing relay 14.1 and closes a circuit that en A tends lfrom ground by way of armature 147 -and its baelecontact, winding of stepping magnet 146, armature 149 and .its haclecontact, bank contact with which wiper 163 is' in engagement and said wiper, and-.armature 152 and its back 'contact to battery. The

magnet 146 operates to restore the wipers- Y to 16?, lnclusive,.to normal posltionr' By this oprration, the circuit ofsthe relay 112 is opened and this -relay isdcenergizeth te open the circuit'cf the stepping magnetv 100v of the finder switch .Fwher'cby .the rota';

tion of the wipers ofthe finderswitch ceases.

The slow-releasing relayz 141, upmrretracte. i

ing its arn'iatures,'opens'.-the .circuit of-the slow-releasing relay 142;/

ture to cause thefrestoration of the 'connector 1n the manner; described-1n connection with the connector H-1'.

Responsive to@ the d eennergization -of the relay 144, theline rclay- 200 'ofthe connector H is released and the' relay retracts its armas.

In the manner'above described, the connection is'. released inresponse to the trans` mission' of. the sending'v operation.

calls to beevenly distributed over the' gro-up of ukeys. '1- To explain morev .fully, 'assuming that another relay,'suchl as 106, is operated in addition to said relayfbythe.momentary operation of another key, such as K, if it were .not-forth'eprovision mentioned, the, code i' corresponding to the operated AreljayjwouldI he transmitted indefinitely -untl 'the proper 'answer-back signal is recorded onli-the lamps,

this diliculty isobviated. and one transmitting operation cannot Vindefinitely prevent` the remaining operations'.

The relay 113,v of course, is dcenergized as soon as the switch wiper 126 is rotated .f rom engag ement with the bankcontact l30and .'lhe reason .that the Vindcr switch F is given a number of steps at' the end uithe- -code-transmittmg operation 1s to permitthe 

